While I was one of the first to try out this commercial DNA service, I certainly haven't been the last.

At last count, 23andMe has 35,000 customers. Curious people gave their spit, so their DNA could be unraveled and give them more information about their health and about their family.

The results are given to customers through an online profile. By logging into the Facebook-like profile, the customers can see information about their health risks and have access to clues about their ancestry.

But the services face an even more fundamental problem: in most cases, the current level of DNA scanning technology and science is unable to offer meaningful predictions about the risk that a person will get a disease.

ancestry painting. Co-founder Linda Avey told me she likes looking at my ancestry painting because it is evenly split. One chromosome is Asian and the other is European. Usually, the chromosomes have multiple colors throughout — not mine.

health. carrier status. disease risk. drug response. traits. cutting-edge research. If you read, My DNA Diary, you'll find out way too much information about me (and my DNA). But at least you'll know what you are getting into if you decide to buy 23andMe's test today.

But, you'll have to decide quickly if you want to spend money on a DNA test. The offer is only valid today. And you can't exactly go on a shopping binge because the company has capped purchases at 10 tests per person.